WO2004004471A2

WO2004004471A2 - Method for producing food-flavouring smoke by pyrolysis, use of a reactor specially adapted therefor, resulting food-flavouring fumes and food products

Info

Publication number: WO2004004471A2
Application number: PCT/FR2003/002087
Authority: WO
Inventors: Pierre Holzschuh; Georg BÜCH; Jean-Jacques Weiland
Original assignee: SOFRAL SOCIETE FRANCAISE D'ALIMENTATION S.A. (Société Anonyme)
Priority date: 2002-07-05
Filing date: 2003-07-04
Publication date: 2004-01-15
Also published as: WO2004004471A3; AU2003264690A8; CA2398681A1; FR2841745A1; AU2003264690A1; FR2841745B1

Abstract

The invention is related to the production of smoke for flavouring agri-food products and concerns a method characterized in that it essentially comprises steps which consist in: introducing the organic material to be pyrolyzed in a reactor essentially including a substantially sealed chamber capable of being heated comprising at least one vibrating rising tubular element receiving said material, in the lower part of said tubular element, heating said organic material to a temperature ranging between 200 °C and 800 °C, preferably between 300 °C and 400 °C, so as to cause it to be pyrolyzed during its displacement, under the effect of the vibrations, in the rising tubular element(s) and extract the consumed material and the smoke produced in the upper part of said tubular element(s).

Description

Process for the production of food smoke by pyrolysis, use of a reactor particularly suitable for said process, smoke and smoke foodstuffs obtained

The present invention relates to the field of agrifood and more specifically that of the production of food flavorings by pyrolysis of vegetable organic materials. It relates more particularly to the production of smoke, in particular liquid smoke, using a process employing a pyrolysis reactor of the electric vibrated elevating reactor type.

Smoking is, along with salting, one of the oldest food preservation techniques. Indeed, it was born soon after man had mastered fire. Originally, the aim was to increase the shelf life of the treated product. Subsequently, it is mainly the search for a taste quality and incidentally that of a mode of presentation of the product, which prevailed.

Archaic processes were used until the last century, but since then the techniques have been modernized and diversified, the traditional smoking methods representing only a small volume on a global scale.

Thus, new products have, for example, ^emerged in the United States from the nineteenth century. These products, also called liquid smoke or liquid smoke compositions, have been developed to replace direct contact of the food with the smoke and are obtained by condensing the gaseous fumes obtained by pyrolysis of a vegetable organic matter, most often wood, in liquid form.

It is in fact known that the pyrolysis of plant materials, in particular the pyrolysis of particles or wood shavings, induces the formation of aromatic molecules during the thermal decomposition processes of said plant material. The chemical nature of the aromas obtained essentially depends on the processing parameters, such as the pyrolysis temperature, the residence time or even the gaseous atmosphere used during the pyrolysis reaction. Furthermore, most of the chemical compounds constituting the smoke obtained during pyrolysis is liquid at room temperature. Due to multiple benefits, these products tend to gradually establish the new production standards for smoked foods. Thus the liquid fumes are used in particular advantageously during the smoking of hams, sausages, fish, breasts, etc., a smoked taste as well as a typical brown coloring, similar to those observed during traditional smokes being then obtained.

Liquid smoke is a complex mixture that can include more than 1,000 different chemical compounds, 400 of which have been clearly identified. These compounds generally belong to chemical families, the main ones being carboxylic acids, carbonyls, phenols and polycyclic aromatic hydrocarbons. As an example of a typical composition of liquid smoke, mention may be made of US Pat. No. 3,106,473.

Schematically, it is accepted that organic acids have an action on the preservability of smoked foodstuffs, that phenols have an action on the taste of smoked foodstuffs and that carbonyl compounds are at the origin of the color of smoked products. However, due to the extreme chemical complexity of liquid fumes, synergies between the different chemical compounds are more than likely.

A number of undesirable compounds are also produced during the pyrolysis processes. Polycyclic aromatic hydrocarbons (PAHs) are toxic compounds produced during high temperature pyrolysis of organic matter. These compounds must be eliminated from liquid smoke or their content must, at the very least, be minimized. The standards currently in force in Europe impose a maximum level of 10 ppb of benzo [a] pyrene and 20 ppb of benzoanthracene in liquid fumes.

Controlling the levels of polycyclic aromatic hydrocarbons in liquid smoke thus minimizes health risks compared to traditional smoking methods. For the production of aromatic fumes, various pyrolysis reactors have been developed in recent decades.

In a first type of reactor described in US Pat. No. 4,298,435, the pyrolysis can be carried out in a rotary oven inclined at an angle of 5 °. Such an oven consists of a rotary calciner comprising a stainless steel tube which can be brought to the desired temperature. Wood enters the tube at a temperature of 480 ° C so that the only oxygen supply comes from the air entrained by the sawdust at the time of loading.

In a second type of reactor described in US Pat. No. 3,875,314, the pyrolysis is carried out using a conveyor which passes into a chamber where a temperature between 600 ° C and 750 ° C prevails.

In a third type of reactor described in US Pat. No. 4,994,297, ultra-rapid pyrolysis known as “flash” (temperature rise rate of 1000 ° C./s) makes it possible to produce liquid fumes having a carbonyl / phenol ratio higher than the fumes obtained by conventional methods. The smoke produced by this type of reactor has a more pronounced coloring power but brings a less intense smoky taste to the processed food products. The yield of pyroligneous juice is very interesting, since it is much higher than that obtained by conventional pyrolysis. Wood or cellulose sawdust is heated between 450 ° C and 650 ° C in 1 second. The residence time of the gases emitted is from 0.03 seconds to 2 seconds in the reactor and then the gases are evacuated (in less than 0.6 seconds) in order to cool them to 350 ° C.

In a fourth type of reactor described in US Pat. No. 4,883,676, the pyrolysis is produced by ensuring a sweeping of dry air at high temperature over a thin layer (2 cm maximum) of dry sawdust. The yield then reaches 90% instead of 45-50% by conventional methods. The gas produced is very rich in condensable compounds and no tar is produced, said sweeping limiting the secondary reactions which are precisely at the origin of the formation of tar. When operating in batch, the pyrolysis temperature must be 600 ° C, while when working semi-continuously, the optimal pyrolysis temperature is only 290 ° C.

Wood pyrolysis can also be carried out under water vapor as described in US Pat. No. 4,359,481, the pyrolysis temperature then being 400 ° C.

However, most of these installations and methods do not allow strict control of the pyrolysis temperature or the residence times. Another process has been described by French patent FR 2 680 638 B1 relating to the roasting of only food products (malt, cocoa, coffee, almonds, etc.). German patent application DE 35 04 950 A1 also relates to the roasting of coffee in a vibrating helical reactor. However, nothing indicates or suggests in these last two publications that such reactors would be suitable for the production of food fumes, in particular the production of liquid fumes, the aim of these processes being above all to recover a roasted foodstuff.

The present invention aims to overcome at least some of the aforementioned drawbacks.

To this end it relates to a process which is similar to a destructive distillation or a thermo-modification of vegetable substances, in particular wood.

In accordance with the present invention, the process for producing fumes intended for the smoking of foodstuffs, said fumes being obtained by pyrolysis of an organic material, preferably vegetable, is characterized in that it essentially comprises the steps consisting in:

introducing said organic material to be pyrolyzed into a pyrolysis reactor essentially comprising a substantially hermetic heatable enclosure containing at least one ascending tabular element vibrated and receiving said organic material, said material being introduced at the bottom of said tubular element,

- Heating said organic matter in said enclosure to a temperature between 200 ° C and 800 ° C, preferably between 300 ° C and 400 ° C, in order to cause pyrolysis during its movement, under the effect of vibrations , in the ascending tubular element (s) and,

- Extract the consumed organic matter and the fumes produced at the top of said tubular element (s).

The present invention also relates to the use of a vibrated elevating reactor of the type essentially comprising a substantially hermetic heatable enclosure containing at least one ascending tubular element vibrated and receiving an organic material to be pyrolyzed, for the production of fumes intended for a smoking of foodstuffs, for the production of liquid fumes and for the production of charcoal.

It also relates to the fumes intended for the smoking of foodstuffs obtained by the process according to the invention, characterized in that they have a benzo [a] pyrene content by volume of 10 μg / m ³ and 20 μg / m ³ by volume of benzoanthracene, ie, once condensed into liquid fumes, a volume content of benzo [ a] pyrene of at most 10 ppb and a volume content of benzoanthracene of at most 20 ppb, as well as the liquid fumes obtained by condensation of said fumes.

Finally, it also relates to a foodstuff smoked by the implementation of smoke or liquid smoke according to the invention. The invention will be better understood from the description below, which relates to a preferred embodiment, given by way of nonlimiting example.

The object of the process according to the present invention is to produce fumes by pyrolysis of an organic material, preferably from the pyrolysis of particles of wood or vegetable matter.

Advantageously, this smoke can be condensed in liquid form in order to produce products also called "liquid smoke".

According to the invention, the process for producing fumes intended for the smoking of foodstuffs, said fumes being obtained by pyrolysis of an organic material, preferably vegetable, is characterized in that it essentially comprises the steps consisting in: :

introducing said organic material to be pyrolyzed into a pyrolysis reactor essentially comprising a substantially hermetic heatable enclosure containing at least one ascending tubular element vibrated and receiving said organic material, said material being introduced at the bottom of said tubular element,

- Extract the consumed organic matter and the fumes produced at the top of said tubular element (s). Advantageously, the tubular element or elements are driven by a vibratory movement having a horizontal and / or vertical component. In a particularly useful variant, the method according to the present invention is characterized in that the organic material is dried by preheating before being pyrolyzed, preferably in at least one specific preheating zone provided in the tubular element or elements and more preferably by electric heating of said zone or zones by the Joule effect.

Thus, it becomes possible to treat all types of organic matter in the same device. The temperature and the preheating time and the residual humidity level can be determined by a person skilled in the art depending on the nature and the amount of organic material used. However, care should preferably be taken not to cause pyrolysis during said preliminary drying operation. In other words, the preheating temperature of the organic material is preferably lower than the pyrolysis temperature of said material, preferably less than 200 ° C.

According to another characteristic, the heating of the organic material with a view to its pyrolysis takes place by direct heating of the tubular element or elements, preferably by electric heating by the Joule effect. The electric vibrated elevating reactor allows continuous heat treatment of plant materials with strict control of the treatment parameters. The treatment possibilities of the electric vibrated elevating reactor allow to produce fumes, liquid fumes, thermally modified wood chips, as well as charcoal. The present invention thus allows a perfectly controlled pyrolysis of the plant material.

The liquid fumes thus obtained can be used by spraying an air-distillate mixture of smoke directly into the smoking cell, soaking, showering or even by direct addition to the foodstuff. The smoke contains no tar or harmful polycyclic aromatic hydrocarbons. The smoke thus produced corresponds to the entire aromatic fraction resulting from the pyrolysis of wood obtained by traditional methods.

A REVE type reactor (electric vibrated elevating reactor) particularly well suited to the process according to the present invention is that marketed by the company REVTECH (Charmes sur Rhône), subject of French patent 91 10 935 published under the number FR 2 680 638 A1. A treatment oven similar to that described in this patent, in German application DE 35 04 950 or any other type of suitable vibrated oven, independently of the heat source used to initiate the pyrolysis reaction proper, are also suitable as reactors with pyrolysis used in the context of the process of the present invention and the latter is therefore not limited to these two examples of particular devices.

Such a REVE type reactor advantageously combines the technology of transporting particles by vibration and the technology of the current flow tube, and thus allows access to advanced techniques for heat treatment of divided solids. This reactor thus allows continuous heat treatment of the organic material to be pyrolyzed.

The organic matter to be pyrolyzed is transported by vibration according to the principle of elevating turns. The organic matter to be pyrolyzed is introduced in a conventional manner (manual or automatic feeding, hopper, etc.) at one of the ends (preferably from the bottom) of the tubular element or elements and evolves under the effect of the vibrations imparted to said tubes. to the other end (preferably upper) where it is recovered in a conventional manner (recovery tank or the like). The vibrations can, for example, be generated by a vibrating table driven by a motor member capable of communicating to said table vibratory movements in a horizontal plane, for example a rotation, and vibrations in the vertical direction. For this purpose, the vibrations can be generated in a known manner by motors with unbalances or any other equivalent device.

The tubular element or elements pass through a fixed enclosure which makes it possible to supply calories and to raise the temperature of said tubular element or elements either directly or indirectly. As a preferred example, the passage of an electric current through the transport tube makes it possible to generate heat by Joule effect in the mass of the tube.

The tubular element (s) may consist of a perfectly closed stainless steel coil. The treatment atmosphere can therefore be strictly controlled. The treatment of organic matter can therefore be carried out under inert gas (nitrogen or any other inert gas), under partially oxidizing gas (nitrogen / oxygen mixture at different oxygen concentrations) or under carbon dioxide or under recycling of fumes produced (recycling of pyrolysis gases during heat treatment).

In a particularly advantageous manner, the method according to the invention is therefore characterized in that the fumes produced are condensed on leaving the reactor in a suitable condensation device.

Advantageously, at least part of the pyrolysis gases present at the outlet of the condensation device is reinjected into the reactor. According to another characteristic, the method according to the invention is further characterized in that the pyrolysis takes place under precise control, to the nearest 0.1%, of the volume content of oxygen in said reactor and according to another characteristic the pyrolysis takes place made under precise control, to within one degree Celsius, of the temperature prevailing in said reactor. Controlling these last two parameters advantageously makes it possible to reduce the risk of fire in the installation, unlike most existing smoke generators.

The residence times of the organic material to be pyrolyzed can also be set precisely. Indeed, the vibrating tube technology allows a “piston” flow of the material to be treated. Thus, the inclination of the unbalance motors as well as the frequency and the amplitude of the vibrations make it possible to control the residence time of said material in the reactor. This residence time can vary, depending on the conditions, from a few seconds to about 30 minutes. The technology of transport by vibrating tube makes it possible to treat divided solids with wide particle size allowing to implement a wide range going from micron powders to pieces of several centimeters of organic matter.

Advantageously, the pyrolyzed organic material essentially consists of wood chips, in particular wood intended for the flavoring or aging of wines and / or spirits.

According to a variant, the pyrolyzed organic material essentially consists of fibers or shavings of at least one vegetable substance such as wood, cellulose, any other polysaccharide or lignocellulosic complex.

As explained, the pyrolysis temperature (from 200 ° C to 800 ° C) as well as the temperature profiles are perfectly controlled at degree close. The possibility of an electrical architecture making it possible to implement several independent heating zones makes it possible, if necessary, to control the thermal profile for processing the plant material. The establishment of a cooling zone, by the use of a few non-insulated turns or by double jacket containing a cold fluid, makes it possible to obtain low and constant temperatures of the pyrolyzed material at the outlet of the reactor.

The thermal decomposition of organic matter and in particular of wood is preferably obtained at low pyrolysis temperatures using REVE type reactors (mainly between 300 ° C and 400 ° C). The fumes and liquid fumes then contain little polycyclic aromatic hydrocarbons which are generally formed at high pyrolysis temperatures (above 400 ° C.).

The present invention also relates to the use of a vibrated elevating reactor of the type essentially comprising a substantially hermetic heatable enclosure containing at least one ascending tubular element vibrated and receiving an organic material to be pyrolyzed, for the production of fumes intended for a smoking of foodstuffs, for the production of liquid fumes as well as for the production of charcoal.

The advantages of using a REVE type reactor for heat treatment of plant materials are manifold:

A homogeneous heat treatment of organic material with variable particle size (for example sawdust from a few microns to several centimeters) is possible by "piston" advancement of the material in the reactor and by intimate contact between the plant material and the hot tube. The “piston” flow makes it possible to precisely control the temperature of the material and the residence times.

Heating is provided by conduction between the tube and the plant material. The process does not require the use of large quantities of gas to be managed or decontaminated. The risks of cold areas (soot traps) are minimized.

The tightness of the system, without mechanical parts, makes it possible to minimize the risks of odors emitted and exposure of personnel to pyrolysis gases. The cleaning of the installation is easy by pyrolysis in air, by circulation of cleaning liquid in the turns or even by scraper shell.

The thermal efficiency of the device is close to 80% by intimate contact between the plant material and the hot transport tube as well as a complex combination of conduction, induction and radiation towards the product to be heated.

Transport by vibrating tube does not cause abrasion of the organic material to be pyrolyzed and limits emissions of carbon powders. The fouling of the reactor by soot deposits is not very significant.

Consequently, the reactors of the type mentioned above can advantageously be used for the production of fumes. Indeed, the process using vibrating tubular elements makes it possible to produce a smoke whose quality and concentration are perfectly controlled while minimizing the risk of fire.

In this regard, it is particularly important to be able to control, in a process implementing such a type of reactor, the main operating and treatment parameters that are the temperature of the pyrolysis (controlled to within Celsius degree) and the chemical constitution of the treatment atmosphere (precise control of the oxygen concentration). Under these conditions, the fumes produced by the process according to the invention can be completely standardized and are advantageously free or almost free of tar and harmful polycyclic aromatic hydrocarbons.

The present invention therefore also relates to fumes intended for the smoking of foodstuffs obtained by the process according to the invention, characterized in that they have, once condensed into liquid fumes, a volume content of benzo [a] pyrene of not more than 10 ppb and a volume content of benzoanthracene of not more than 20 ppb.

In addition, said fumes can be diluted with hot air or any other gas leaving the reactor in order to produce more or less concentrated fumes. They can then directly enter a smoking cell, without any other conditioning or purification step. The present invention also relates to liquid fumes obtained by condensation of fumes according to the invention as well as a foodstuff smoked by the implementation of such fumes.

The following examples, given without limitation, make it possible to demonstrate certain advantages of the objects of the present invention.

Example 1:

Wet beech sawdust (35% by weight of moisture) is pyrolyzed in a REVE type reactor (REVTECH company). The reactor has two heating zones. The first zone is heated to a temperature of 190 ° C while the second heating zone is to a temperature of 340 ° C. The gases emitted by the first heating zone are evacuated outside following dilution with dry air. The second heating zone is swept by a neutral gas. The sawdust undergoes drying in the first zone and enters the second heating zone at a humidity of less than 1% by weight.

Sawdust pyrolysis is exclusively carried out in the second zone where the plant material is brought to 340 ° C then it is rapidly cooled in the cooling coils to 40 ° C.

The emitted gases are evacuated with the nitrogen injected against the current to an indirect condenser. The condensable organic compounds are recovered in the form of a liquid at the outlet of the condenser.

This reactor configuration described in Example 1 allows simultaneous drying and pyrolysis of sawdust from wet beech.

The condensates obtained form a concentrated liquid smoke. In fact, the initial moisture from the sawdust is removed outside the reactor before the sawdust enters the pyrolysis zone.

The liquid smoke obtained has the following characteristics:

Density: 1.11 kg / 1 pH: 1.8

Analysis in gas chromatography (% by weight) - acetic acid: 15%

- carbonyl: 8%

- esters: 4 mg / ml - furans: 15 mg / ml

- lactones: 4 mg / ml

- phenols: 32 mg / ml

Example 2:

Dry beech sawdust (7% by weight of moisture) is pyrolyzed in a REVE type reactor (REVTECH company). The reactor has a single heating zone. The heating zone is brought to a temperature of 320 ° C, 330 ° C, 340 ° C then 350 ° C.

The temperatures measured on the organic matter are respectively 320 ° C, 330 ° C, 340 ° C and 350 ° C. Example 2 perfectly shows the temperature control during the pyrolysis process of the organic matter to be pyrolyzed. No temperature divergence phenomenon is observed despite the existence of exothermic phenomena at such pyrolysis temperatures, for example in the case of wood. The REVE type reactor allows a perfectly controlled heat treatment in temperature and residence time, in particular for sawdust, unlike existing smoke generators.

Example 3:

Dry beech sawdust (7% by weight of moisture) is pyrolyzed in a REVE type reactor (REVTECH company). The reactor has a single heating zone. The heating zone is at a temperature of 350 ° C. Condensable and noncondensable gases are routed to a condenser. The condensable part of the pyrolysis gases is recovered in liquid form at the outlet of the condenser, while the noncondensable gases (essentially carbon dioxide) are used to inert the pyrolysis zone.

The “recirculation” of the incondensable gases allows very rapid and efficient inerting of the pyrolysis zone and makes it possible to dispense with an external supply of neutral gas. The conversion efficiency of the raw material into liquid smoke is 35%. Besides the high conversion efficiency, the smoke obtained does not contain tar. The composition of the liquid smoke obtained after condensation is as follows: Density: 1.11 kg / 1 pH: 1.8

Analysis in gas phase chromatography (% by weight)

acetic acid: 17% carbonyls: 10% esters: 2 mg / ml furans: 20 mg / ml lactones: 0.5 mg / ml phenols: 45 mg / ml

The use of the process according to the present invention therefore makes it possible to produce fumes with a high yield and without producing tars unlike the reactors and generators of fumes currently present on the market.

The liquid smoke obtained according to the invention is rich in aromatic compounds (phenols) and carbonyls. The latter are at the origin of the particularly effective and realistic coloring of the smoked products with the fumes according to the invention due to the Maillard reactions with the proteins contained in said treated foodstuffs.

The indirect condensation of the smoke makes it possible to recover all of the aromas and therefore all of the aromatic fraction contained in the smoke. The tests carried out on deli meats by showering with this liquid smoke reveal a smoked taste of the finished products, identical or even superior to that observed in smoking by traditional methods.

The present invention therefore also relates to a foodstuff smoked by the use of smoke and / or liquid smoke according to the invention.

The REVE type reactor is a very efficient tool for processing plant matter. In addition to the application linked to the production of smoke intended for the smoking of foodstuffs or for liquid smoke, the REVE reactor can also be advantageously used during the heat treatment of fragmented plant materials. For example, the REVE reactor can be used for the production of wood chips for the flavoring or aging of wines and spirits; the aromatic compounds sought being similar to those collected in liquid smoke.

The process according to the invention is also suitable for the production of charcoal or thermally modified vegetable fillers that can be incorporated into composites based on plastic or hydraulic binders.

Of course, the invention is not limited to the embodiment described. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without thereby departing from the scope of protection of the invention.

Claims

1. Process for the production of fumes intended for the smoking of foodstuffs, said fumes being obtained by pyrolysis of an organic material, preferably vegetable, characterized in that it essentially comprises the steps consisting in: - introducing said material organic to be pyrolyzed in a pyrolysis reactor essentially comprising a substantially hermetic heatable enclosure containing at least one ascending tubular element vibrated and receiving said organic material, said material being introduced at the lower part of said tubular element,

heating said organic material by direct heating of the tubular element or elements, preferably by electric heating by Joule effect, in said enclosure at a temperature between 200 ° C and 800 ° C, preferably between 300 ° C and 400 ° C, in order to cause pyrolysis thereof during its movement, under the effect of vibrations, in the ascending tubular element or elements and,

2. Method according to claim 1, characterized in that the tubular element or elements are driven by a vibratory movement having a horizontal and / or vertical component.

3. Method according to claim 1 or 2, characterized in that the organic material is dried by preheating before being pyrolyzed, preferably in at least one specific preheating zone provided in the tubular element (s) and more preferably by electric heating of said zone or zones by Joule effect.

4. Method according to any one of claims 1 to 3, characterized in that the fumes produced are condensed at their outlet from the reactor in a suitable condensation device.

5. Method according to any one of claims 1 to 4, characterized in that at least part of the pyrolysis gases present at the outlet of the condensation device is reinjected into the reactor.

6. Method according to any one of claims 1 to 5, characterized in that the pyrolysis takes place under precise control, to the nearest 0.1%, of the volume content of oxygen in said reactor.

7. Method according to any one of claims 1 to 6, characterized in that the pyrolysis takes place under precise control, to a degree

Celsius close, the temperature prevailing in said reactor.

8. Method according to any one of claims 1 to 7, characterized in that the pyrolyzed organic material consists essentially of wood chips, in particular wood intended for the flavoring or aging of wines and / or spirits.

9. Method according to any one of claims 1 to 7, characterized in that the pyrolyzed organic material consists essentially of fibers or shavings of at least one plant substance such as wood, cellulose, any other polysaccharide or ligno complex - cellulosic.

10. Use of a vibrated elevating reactor for the implementation of the method according to any one of claims 1 to 9, of the type essentially comprising a substantially hermetic heatable enclosure containing at least one ascending tubular element vibrated and receiving a material organic to be pyrolyzed, for the production of smoke intended for the smoking of foodstuffs.

11. Use according to claim 10, for the production of liquid fumes.

12. Use according to claim 10, for the production of charcoal.

13. Fumes intended for the smoking of foodstuffs obtained by the process according to any one of claims 1 to 9, characterized in that they have, once condensed into liquid fumes, a volume content of benzo [a] pyrene not more than 10 ppb and a volume content of benzoanthracene not more than 20 ppb.

14. Liquid fumes obtained by condensation of fumes according to claim 13.

15. Foodstuff smoked by the implementation of fumes according to claim 13 and / or of liquid smoke according to claim 14.